0. No fame is as fleeting as that of a songwriter. It is a perfectly valid reason to become a better singer.
1. If you sing in a style that no one can harmonize, you are a stylist, not a singer.
2. If no one leaving the room can remember a word of your performance, you are a poet with a guitar, not a songwriter.
3. If you are the only person who can "perform your song". see item 2. A good hook with a standard structure beats a long monotone self-confessional every time.
4. Kris Kristofferson wrote with only three chords too. But the lyrics and melody are memorable. See Loving Her Was Easier. Find the version by The Glazer Brothers. Then look them up. Fascinating fellows.
Your job is to write melody, lyrics and chords. Somewhere in those you have to do something really original. Rewrite until you do. Quality over quantity.
5. If what you have are raw songs that you can't actually sing well but a pretty face, you can be labeled as "an innovator" but your producer has to do all the musical work. What you are is "product" or as the pros say, "meat". That's ok but you have a very short career ahead. Have an exit strategy known as "a day job". There is no shame in it. In fact, in these post-CD-album days where the song is worth almost nothing and the recording has a little bit more than nothing value, more do it than don't.
6. If you pay for the recording, you own the master. Don't leave it behind. Don't take handshake deals.. You will get screwed. I know that seems cynical and well, yah, these are your friends but listen to Cyndi Lauper, The Wise: money changes everything. Wait for the contract and go over it with a music lawyer.
7. Training. Music lessons on the instrument and voice, analysis of other songs that you didn't write, transcription, all of these pay off big time. You can steal but if you don't make it your own work by knowing how to do that, you can wind up being sued into poverty. It happens. See George Harrison and Ed Sheeran. Successful stealing comes of being a very competent analyst of all things musical. Theory matters. Tech matters.
8. There are these things called rhyming dictionaries, chord catalogs and yes, progression catalogs. Knowing how different styles of music apply these is your ticket to a long career as a songwriter. The markets change about every ten years and you will have to adapt or retire. See Item 4. The three chord progression is less than a quarter of a page of a progression catalog. Maybe expanding your vocabulary, understanding extensions, substitutions, resolutions, etc. is worth your time. A performer may be stuck in the style that made them famous. You don't have to be and shouldn't be.
Part of your education should be Figured Bass, aka, the Roman Numeral chord system. Yes, Nashville uses the Nashville Number System, but figured bass is the most common way to write a progression without an assigned key center anywhere else. You don't know what a key center is? Ummm... ok. Good luck with arranging. No, the main benefit is you will learn chord functions as standalone units of thought. This is very nice to have when you are writing more advanced work. Just a thought.
9. Any time an experienced and usually older writer, musician or producer takes the time to give you feedback, LISTEN AND REMEMBER. That they do that is a grace and a blessing. If you are one of those "don't listen to anyone over fifty" folks who love their own generation and like to disregard what came before or who, you are an idiot. That light at the end of the tunnel of your quest for fame and a seat on the square is a train.
If you are one of those people who curls up in a ball and hides in your room anytime you are criticized, YOU ARE IN THE WRONG BUSINESS. Please, your mental health conditions may interest your therapists but they are wasting your producer and band's time. Being a head case really shouldn't be part of your "brand". We all get it that mental health is a serious issue but if you understand the ADA (disabilities act) as applied, it is possible to have a disability and not be disabled because you can do the job and do. That is your goal.
Stop trying to be cool and start connecting with honest emotions: yours. You will get better at that as you age, so be prepared to write a long time before you write well. Persist.
Don't take journalists too seriously. A puffer in the music business has the same description as a fluffer in the porn industry, just a different shaft. Puff pieces are a regular part of marketing and quite legal, but the advice not to believe your own press is good advice. Trust your ears. As Duke Ellington said, there are only two kinds of music, good and bad. If it sounds good, it is good. Puffery is one means for mobs to take over music scenes. Puffed acts tend to deflate quickly when exposed to enough audiences. As they say in the album "We're All Bozos on this Bus", please deflate your shoes. A big ego is terrible for your posture.
10. Busking may get you noticed but it also means you are a street panderer. It is honorable but come winter, you are just out in the cold sucking in carbon monoxide. The city isn't doing you a favor. It is helping room owners get free music so they can pay real estate developers. You are being used.
An agent that gets you gigs reliably is worth shredding the natch with because they are doing the legwork and political stuff you may not be good at or want to do. Take Care of Business (TCB). Otherwise, it is a good rule to play every gig you can get. If you are planning to be a performer as well as a songwriter, you need a fan base. Live streaming is your friend.
The idea that only the song matters, not the performance, is a ticket to nowhere. There certainly are those who aren't great players or singers, but they are the exception on the other side of the sidewalk.
11. If you turn up to Eleven and are Proud to Be Loud, for God's sake, tune the guitar. Pretty please.
12. Tracks and loopers are fine as long as you know how to make good recordings. See items 1 through 11. If you don't, you aren't trying. These days a home recording setup costs bupkus compared to what you will pay to demo your songs in a commercial studio. The more you can do yourself, the more money you get to keep.
Get a copy of Guitar Pro or something like it and learn to write out parts. Get a copy of Finale (easy) or Sibelius (powerful but hard) and learn to score. This takes time so if you don't have serious classical chops, start with Guitar Pro. It is a tab editor for midi. It has chord catalogs and scale possibilities. Spend time writing out progressions and copying progressions. Use the import/export function to push the midi to other editors like scoring editors. You will learn more that way than almost any other. You can learn what other instruments sound like in your song. You can discover sounds. You can expand your vocabulary, Best of all, you can hand a trained musician a written part. They may not like it but you will learn from that too. This is long term studying but very very worth it.
There may come a time when you have access to professional recording. Very cool. Better gear, better ears, better sound. You will know when that time comes and as long as you can afford it or someone else can, very very cool. Pay attention, don't interfere with the elves at work, do your job and let them do theirs.
Don't be a diva and do prepare. It can be very scary and the time is limited to the budget. The more you do your own recording, the more you know about your sound. Unless you have signed a deal that puts the producer in charge (not a bad thing unless they are bad at this), it's up to you to get your sound. Relax and understand this really is a chance to learn every time you do it. Ask questions but during breaks, not while the engineer is engineering. Above all, keep your hands off the knobs.
13. If you do it for a passion, be passionately good at it. The world is full of mediocrity. No your Mom is not your best critic. You are. Don't compete with the other writers. Compete with the you you were yesterday.
It is ok to play in "old styles" out of the current trends as long as you can play them well. The word "tight" has meaning and being tight has value.
Rehearse. Record your rehearsals and listen. Use that smart phone to get a video of how you look. For songwriters, that last bit isn't too important. For performers, which is what a singer-songwriter is particularly with a band, it is important. Don't let it get you down or rob you of confidence. Just work at it.
It's not ok to stare at the floor.
14. Drugs make you stupid. Sometimes stupid is good. When recording, stupid is never good. Party later. The songwriter drug of choice is: coffee.
15. Take care of your body. I buried friends. It sucks.
16. Collaborators. Some say always. I say only if you have a good productive relationship worked out on paper, signed and notarized. Trust but document. Again, money changes everything including, sometimes, the writer credits. The money is in the publishing and the masters so be very very sure what you are signing up to. Music lawyers may be a nuisance but they are necessary.
17. Some say "always be positive and avoid being negative". I differ. Be honest. Be yourself. Be strong. Sometimes you will go it alone. As they say, the bird flying solo has the strongest wings.
Be wary of those who hide their feelings in music or any business. Often, these are the snakes, the sociopaths who haunt every hall where money is made and who suffer no pain because their ability to be empathic was wiped out before they were out of short pants. It seems smart to be inward when you are hurt and in some situations, it is. But there is a difference between self-control and sociopathy.
Take a lesson from the #metoo movement. In situations where you are being used or abused and you keep that to yourself and do not confront that abuser immediately, you will have a very hard time doing it later and meanwhile, you are being damaged. Sometimes irreparably. God gave you a mouth and a temper for a reason. DO NOT ACCEPT IT AS THE PRICE OF SUCCESS. It never is. Then get out of that room and don't go back.
Trust your judgement and step up. It is your song and you are the champion of your song first and always until someone joins your team. Find them by being open to them and going where they will be.
Avoid clowns and haters. Take care of business as I said above because if you are unhappy and desperate, it shows. Desperation is the worst. It is the grime on your windshield and any serious person will notice it and ask themselves if you are a burden instead of an asset.
18. Study the craft of songwriting. That above all else: get better. Never stop learning. There is a book by a master, "Tunesmith". Written by Jimmy Webb, it covers many aspects of the craft and the business. It is worth every penny and more. See Amazon. Be aware that many many of the veterans are not happy about The Web. They are right. No, it isn't going away, but they are right.
19. You don't have to be a star. In fact, you may not like that as much as you want it. One of the best folks to explain it to me was an old country gentleman named Chet Atkins. He said, "You have talent. Come as a songwriter. I have lots of great guitar players but not enough good songwriters." I didn't listen. I was young and stupid. Don't be me.
20. Live long and leave a beautiful body of work. Your songs may outlive you. That's success.